高速网络流采集系统的设计与实现

针对基于软件的网络流采集系统不能高效处理高速网络流量,以及为了提高采集效率需要同时对多种网络流进行采集的问题,提出一种基于软硬件结合的高速网络流采集框架,探讨在NetFPGA-10G平台实现高速网络流采集系统,称之为HSNTCS。该系统在硬件上通过精确串匹配引擎或正则表达式匹配引擎过滤、分类出所需的多种网络流后,将其传至内核驱动层对应的数据缓冲区,然后直接拷贝至用户空间并存储至对应的数据库。经实验测试,在精确串匹配情况下,用硬件方式实现的高速网络流采集系统的用户数据报协议(UDP)、传输控制协议(TCP)吞吐率都达到1.2Gb/s,约是用软件方式实现的3倍;在正则表达式匹配情况下,用硬件方式实现的高速网络流采集系统的UDP、TCP吞吐率都达到640Mb/s,约是用软件方式实现的3倍。结果表明,相对于软件实现方式,硬件实现具有更高的采集性能。     

Cellular automata on FPGA for real-time urban traffic signals control

Among different traffic features, the urban traffic has received a lot of attention due to the ongoing traffic congestion as a result of increased car usage, population growth, and changes in population density. In urban networks, the vehicles flow differs when compared with highways flow because of the freeway’s low speed limit but mostly because of the traffic lights control. In this paper, a real-time hardware implemented bio-inspired model for traffic lights control is presented. The proposed model arrives from Cellular Automata (CAs), which have been proven very flexible and powerful computational traffic models, in that they are able to capture all previously mentioned basic phenomena that occur in traffic flows. The resulting CA model was hardware implemented on FPGA to take full advantage of the inherent parallelism of the CAs and to support the function of an advanced electronic system able to provide real-time adaptive control of traffic lights designed to consider traffic conditions for the whole intersections. The analytical results, obtained by application of the aforementioned FPGA CA processor are found in excellent agreement with the numerical simulations.     

Carnivore Documents Reveal Enhanced Tapping Abilities

According to documents released by the FBI to the Electronic Privacy Information Center (EPIC), the Carnivore Internet surveillance system is able to capture more than targeted ‘filtered’ traffic.     

基于Libpcap的局域网流量测量系统设计与实现*

介绍了基于Libpcap和BPF包过滤器进行软件抓包的原理;针对局域网环境,在不使用专门的硬件设备前提下,设计并实现了基于Libpcap进行数据采集的流量测量系统。系统中区分了国际国内的流量,方便网络管理员进行流量控制和计费。最后,考虑了不同局域网环境下的部署问题。     

Evaluation of user interfaces: EVADIS II— a comprehensive evaluation approach

Abstract

As a result of the importance of the usability approach in system development and the EC's ‘Directive concerning the minimum safety and health requirements for VDT workers’ (EWG 1990), there is an accepted need for practical evaluation methods for user interfaces. The usability approach and the EC Directive are not restricted to user interface design, as they include the design of appropriate hardware and software, as well as organization, job, and task design. Therefore system designers are faced with many, often conflicting, requirements and need to address the question, ‘How can usability requirements comprehensively be considered and evaluated in system development?’ Customers buying hardware and software and introducing them into their organization ask, (How can I select easy-to-use hardware and software?’ Both designers and customers need an evaluation procedure that covers all the organizational, user, hard- and software requirements. The evaluation method, EVADIS.II, we present in this paper overcomes characteristic deficiencies of previous evaluation methods. In particular, it takes the tasks, the user, and the organizational context into consideration during the evaluation process, and provides computer support for the use of the evaluation procedure.     

MEHARI: a system for analysing the use of the internet services

This paper describes the MEHARI system for monitoring and analysing the traffic on National R&D Networks (NRN). The main design requirement of the MEHARI system was to cope with the main challenges currently faced by most of these networks: Service usage, charging schemes, network dimensioning and auditing procedures according to a given Acceptable Use Policy (AUP). The resulting MEHARI system consists of a low cost hardware traffic capture platform, and several traffic analysis software modules running on top of this platform. These modules can report information on the usage of the Internet services, the main traffic origin and destinations, etc. The MEHARI system has been tested by running a field trial on the Spanish NRN (RedIRIS). Some relevant data on the performance and efficiency of the system configuration used in the field trial is presented in this paper.     

The new mexico state university ring-star system: A distributed unix environment

A distributed version of the UNIX operations system is currently under development through a joint effort of New Mexico State University and the Hebrew University of Jerusalem. A microprocessor version of the UNIX kernel has been developed which will run on any PDP-11 or LSI-11 based processing element and allows processes to run in a UNIX ‘look-alike’ environment. Each process is fully transportable among all processors in the system. Although the preliminary version of the system was built in a star configuration, the system is currently being upgraded by the addition of a communication ring with 8-bit microprocessors as ring interface units. The current paper describes the software structure, the hardware structure and the communication protocol of the system.     

An integrated design of a satellite-based navigation system for air traffic control

This paper focuses on the microprocessor-based computer architecture necessary to integrate the Department of Defense's Global Positioning System into the Federal Aviation Administration's (FAA) main frame computers. It incorporates what is defined as an Automated Dependent Surveillance (ADS) concept for air traffic control. The ADS system is dependent upon receiving position information from the aircraft's equipment as opposed to the independent ‘skin paint’ received from a radar.After a brief introduction and background, the authors' detailed design is presented depicting the distinctive manner in which the hardware and software were committed and modified in the main frame computer and the design approach for the avionics equipment to permit the Global Positioning System to be employed for air traffic control.     

Dedicated,distributed and portable operating systems: A structuring concept

Primarily economic reasons have created a growing need for the development of operating systems providing support for existing and newly developed structurally different hardware systems–-operating systems which (a) implement functionally different problem-oriented solutions without imposing the need of developing problem-invariant functions repeatedly (‘operating system family’) (b) work not only in a local environment, but also co-operate with one another in an interconnected hardware system, thus appearing to the user as only one big operating system (c) are portable among structurally different hardware systems independent of one another (‘autonomous systems’), as well as among structurally different interconnected hardware systems (‘networks’) We present some principles of a structuring concept which seems to be a suitable means of developing operating systems with the specified characteristics in an economic and controlled manner.     

流量分析系统TAS的设计实现

留量分析系统可以应用于网管,也可以作为入侵检测系统的一部分。提出了一种可扩展的流量分析系统,可以使用各种插件来处理报文,以统计流量和检测入侵。PCAP采集端捕获报文后,交处理端分析。该处理端使用加权流量对主机列表进行排序,根据二八原则来减少内存的消耗。然后利用各种插件对报文、处理端结果进一步进行分析。在插件部分,介绍了插件的结构和数据导出插件的原理,该导出插件基于RRD。     

A video streaming application for urban traffic management

Urban traffic control systems have based their technological infrastructure both on advanced analog close-circuit television systems (CCTV) and point-to-point links, providing difficult-to-scale and very expensive systems. The main goal of an urban traffic monitoring system is to capture, send, play and distribute video information from the streets of a certain city to a management centre where it is processed by different services. Current digitalization process of video networks, and the research carried out in the field of streaming media, has led vendors to present proprietary hardware and software solutions resulting in a strong dependency by their customers. This work presents an open urban traffic control system based in commercial off-the-shelf (COTS) philosophy for hardware and software components, as well as open source and standardized protocols. The existence of open standards for video encoding and protocols for streaming media transmission over IP networks has led to the proposal of such a system. The proposed system is a suitable solution in terms of scalability, cost, interoperability and performance for traffic control systems. Furthermore, its architecture can be easily adapted to other video applications and tools like command and control, surveillance or security systems for military and civilian applications.     

Enablers and barriers to the use of ICT in primary schools in Turkey: A comparative study of 2005–2011

The purpose of this study was to reveal barriers encountered by Turkish primary school teachers in the integration of ICT, to propose potential enablers to overcome those barriers, and to compare the current status of ICT integration (in 2011) with the status of ICT integration in 2005. Part of the data for this comparison was gathered in 2005 as part of a doctoral study by Goktas (2006). A survey design was used to investigate the barriers and enablers. Data were collected from 1373 teachers from 52 schools in 39 provinces. The results indicate that ‘lack of hardware’, ‘lack of appropriate software materials’, ‘limitations of hardware’, ‘lack of in-service training’, and ‘lack of technical support’ were the most important barriers. The highest ranked enablers were ‘allocation of more budget’, ‘allocation of specific units for peer support’, ‘allocation of support offices and personnel for teachers’, and ‘offering higher quality pre-service training for ICT’. Other leading enablers were ‘supporting teachers to enable effective ICT use’, ‘having technology plans’, ‘offering higher quality and more quantity of in-service training’, and ‘designing appropriate course content/instructional programs’. Analysis of an independent t-test revealed that most barriers showed significant differences and most enablers showed moderate or low differences between teachers' perceptions of their situation in 2005 and in 2011.     

Improving network security through port switching

The latest rage in network performance improvement is the use of switching technologies to isolate traffic from various systems. This is achieved by placing a system on a device called a switching bridge which, in turn, isolates traffic by only allowing packets to be sent to the port on which the system is located when a packet is actually addressed to the system in question or when the message is a group or broadcast message that would be sent to all nodes. In a typical LAN environment, systems on a network segment ‘see’ each other's data packets which introduces a performance and security problem. With switching technology, it is possible to isolate traffic from system to system which has the effect of not only improving performance, but also improving security—you cannot collect data from the network you cannot ‘see’.     

典型交通场景下智能车的定位与协作

提出并设计了基于多智能体的多智能车协作系统平台,包括基于嵌入式多车协作系统的硬件、软件及通信协议,该系统可作为多车协作算法的仿真实验平台。针对典型城市交通场景,提出了基于拓扑结构的两层地图模型,并采用视觉与里程结合的方法实现智能车在地图中的准确定位。在此基础上,设计了基于冲突表的路口协调算法、车队跟随算法,并完成路口、车队、超车等协作任务,通过实验结果证明了多车协作系统定位与协作的可行性和可靠性。     

Identification of probe request attacks in WLANs using neural networks

Any sniffer can see the information sent through unprotected ‘probe request messages’ and ‘probe response messages’ in wireless local area networks (WLAN). A station (STA) can send probe requests to trigger probe responses by simply spoofing a genuine media access control (MAC) address to deceive access point (AP) controlled access list. Adversaries exploit these weaknesses to flood APs with probe requests, which can generate a denial of service (DoS) to genuine STAs. The research examines traffic of a WLAN using supervised feed-forward neural network classifier to identify genuine frames from rogue frames. The novel feature of this approach is to capture the genuine user and attacker training data separately and label them prior to training without network administrator’s intervention. The model’s performance is validated using self-consistency and fivefold cross-validation tests. The simulation is comprehensive and takes into account the real-world environment. The results show that this approach detects probe request attacks extremely well. This solution also detects an attack during an early stage of the communication, so that it can prevent any other attacks when an adversary contemplates to start breaking into the network.     

A fast parallel algorithm for dot linking in Glass patterns

The human visual system is very good at perceiving structure in complex patterns. ‘Glass patterns’, constructed from displaced copies of random dot patterns, are examples of this in which the only cues are pairs of matching dots. Stevens has proposed a model that accounts well for human performance at this task. A modified version of this model is proposed here which has a fast implementation on parallel ‘pyramid’ hardware. The existence of such implementations is highly desirable because human perception takes place very rapidly. The hardware assumed is a stack of cellular arrays each of which covers the image with a different size grid. This architecture allows fast communication between distant parts of the image as long as the amount of information that needs to be sent over long distances is limited. The modified model was found to behave quite similarly to Stevens' model.     

高速网络环境下的入侵检测技术研究综述*

高速网的普及应用对入侵检测技术提出了更高要求,传统的方法已难以适应处理大流量的网络数据。对入侵检测过程进行分析,指出高速网络环境下制约入侵检测效果的不利因素和难点,强调应从数据包捕获、模式匹配、负载均衡、系统架构等方面入手,充分利用软件的灵活性、专用硬件的并行性和快速性来提高入侵检测系统的性能,以适应高速的网络环境。     

基于帧间差分法的目标检测研究与FPGA实现

针对以往帧间差分算法的硬件实现架构中数据同步信号设计复杂,调试周期较长的特点,设计了一种新型的硬件算法架构。整个系统基于Altera的Cyclone Ⅳ E系列进行开发,采用镁光的SDRAM作为高速储存器件,豪威科技的OV5640作为图像采集器件。该系统对采集到的原始图像数据进行灰度化处理,利用硬件差分算法模块对灰度图像进行差分处理与二值化,实现对视频图像中动态目标的捕捉。基于Quratus Ⅱ与Modelsim联合开发平台对系统进行硬件设计和功能模块仿真。硬件测试结果表明,系统能够清晰地检测出视频中的动态目标,且具备较好的实时性。     

过程级动态划分的RSoC软硬件双通信模式

软硬件通信模式的选择对软硬件通信效率产生很大影响.根据硬件函数的特点,提出一种根据软硬件通信量自适应地选择通信模式的软硬件双通信模式,并构建了一种通信模式自适应决策算法,软硬件通信模式的选择对用户透明.实验表明,根据运行时系统状态自适应地选择通信模式,软硬件通信效率得到优化,面积开销也适当减少.